The long term objective of the research proposed here is to develop a rapid enzyme linked immunoassay for toxigenic C. difficile. C. difficile is the most frequent cause of antibiotic-associated diarrhea and colitis and the second most frequently identified cause of enteric disease in industrialized nations. Single treatment of patients with virtually any antibiotic can induce an overgrowth of intestinal microflora by C. difficile and cause disease. A very reliable diagnostic procedure which detects an exotoxin, Toxin B, already exists but requires 48 hours to perform and a sophisticated cell culture facility. Although effective therapy exists for C. difficile, it is usually withheld until the results of the cellular assay are known because a majority of samples assayed lack toxin. An alternative assay should require less time while preserving specificity for Toxin B. The investigators have developed a panel of murine MAbs specific for Toxin B, high titered Toxin B specific antisera, and purification methods for Toxin B. The research plan in this proposal will make use of conventional immunological methods to develop an antigen capture test using these reagents as they have previously done with adenovirus and rotavirus.